The present invention relates generally to the field of electrical connectors and more particularly to electrical connectors that are shielded against the flow of ratio waves and electromagnetic waves. These waves may interfere with the transmission of electrical energy and more particularly electrical signals transmitted through wiring and conduits located within the electrical connector.
More particularly the present invention relates to a generally electrically conductive outer connector element that contains an inner electrically insulated element that is capable of transmitting electrical current and electrical signals through the wires and conduits within the connector while the wires and conduits are shielded from outside radio frequency waves (rf) and electromagnetic (em) waves. The relationship and sliding fit of the between the outer connector element and the inner insulated element.
In the DOT STAR electrical sensor system for stopping a railroad train when a derailment or wheel failure system arises, as best described in U.S. Pat. Nos. 3,929,308; 3,930,629; 4,029,859; issued to John Armstrong et al, there are several instances where it is necessary to transmit electrical signals and electrical current from one movable part of a train wheel or train system, to a final or fixed and stationary part within the train wheel suspension system. In this art a pair of wheel and axle sets combined with side frames and suspension is called a "truck". The "truck" requires a number of electrically powered appliances and other electrically responsive equipment that utilizes transmission of electrical current and electrical signals through one or more electrical conduits or cables.
The "Dot Star" system that is covered by the patents set forth above requires electrical power and transmission of electrical signals in connection with the safety features practiced by the "Dot Star" system.
In experimenting and working with the DOT STAR sensor system the inventors found that there was need for a specially designed electrical connector having an outer fully electrically conductive member with a special designed inner connector element that is electrically insulated from the wires or conduits located within the inner connector element. In such an arrangement the outer member must be fully capable of shielding the inner member from the flow of radio frequency waves and electrically magnetic waves so as not to interfere with electrical signals and electrical input or current carried through the wires and conduits carried within the confines of the insulated member.
In order to solve the problems associated with completely shielding the electrical conduit and electrical wires from radio frequency waves (rf) and electromagnetic waves (em) as well as facing the problems of twisting stress associated with electrical wiring that is fixed on one end, and being subjected to rotation and turning stress on the other end it was necessary for the inventor to design a connector having an outer metallic element that is electrically conductive and an inner protective element that is generally electrically insulated, wherein the electrical wires, conduits and signal transmitting cable means that are to be protected are located inside the inner, insulated flexible connector element.
In the prior art there was no known electrical connector that permitted the rotational flexing of a wire braid conduit at its termination point on the connector and integrally incorporating a 360.degree. degree radio frequency waves (rf) or electromagnetic wave shield termination means in the same connector.
In the prior art devices shielded and insulated connectors terminated in such a way that there was either leakage of RF waves or em wave leakage at that point so that there was interference with any interior electrical signals or electrical current transmissions. Use of the prior art devices caused many DOT STAR failures due to RF or EM interference causing unnecessary and dangerous time consuming train stoppages by transmission of false signals given by leakage or transmission of RF or EM wave signals to the DOT STAR sensor system.